Brightening agents



United States Patent 3,157,644 BRFGHTENENG AGENTS Franz Marschall and Harlan B. Freyermnth, Easton, Pa, and William W. Williams, New York, N.Y., assignors to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Apr. 4, 1956, Ser. No. 575,925

' 3 Claims. (Cl. Mil-24d) This invention relates to novel bistriazole compounds possessing new and useful properties which render them particularly useful as fluorescing optical bleaching or whitening agents.

It is well known that textiles tend to develop a yellowish shade on aging which cannot be removed by ordinary methods of bleaching or washing. The heretofore used methods of bluing white materials with blue pigments or fugitive blue dyestufis have become quite obsolete in modern laundry practice and have been largely superceded by methods employing fluorescent optical bleaching agents or brighteners as additives to the soap or detergent in the washing bath. These brightening agents are usually conveniently supplied commercially in the form of intimate admixtures with the soap or detergent in bars, flakes, powders, etc. The fluorescent optical bleaching agents perform'their desired function by virtue of their characteristic absorption of ultra-radiations and subsequent conversion of this energy to light energy within the visible spectrum. This converted and emitted light energy tends to neutralize any yellowness of the material and thereby increase the apparent whiteness thereof.

Compounds which have been suggested and employed as fluorescent brightening agents include the following:

I. Acylated derivatives of 4,4-diamino-stilbene 2-2'- disulfonic acid.

II. Acylated derivatives of 4-4-diamino-diphenyl-2-2'- disulfonic acid. I

III. Triazyl derivatives of diamino stilbene disulfonic acid.

IV. Triazyl derivatives of diamino diphenyl disulfonic acid.

V. Acylated derivatives of diamino dibenzothiophene dioxide, etc.

Compounds of the Types I and II are disclosed in US. Patents 2,581,059 and 2,643,198 and in British Patent 584,484.

Compounds of the Types III and IV are disclosed in US. Patent 2,618,636 and in application Serial No. 381,- 856 published May 11, 1943, now US. Patent 2,926,259, by the ARC.

Compounds of Type V are exemplified in US. Patents 2,563,493 and 2,563,795.

In addition to the five types mentioned above, other triazyl compounds have been suggested. Thus US. Patent 2,668,777 discloses a bistriazole of the formula:

NBQgS- -SOaNS.

There are other known compounds containing both stilbene and triazole moieties but such compounds are not brightening agents for the purposes herein contemplated but rather are yellow dyes.

The compounds of the present invention are 4-(2-substituted-7-benzo[l,2,3,4]bistriazole) stilbenes devoid of chromophoric groups and have the following general for- I H I I wherein B represents a benzene nucleus which may contain a substituent such as hydrogen, halogen, such as chlorine, bromine and the like, alkyl such as methyl, ethyl, propyl and the like, alkoxy such as methoxy, ethoxy, n-propoxy, n-butoxy and the like, B represents a benzene nucleus which contains a substituent such as or sulfo (SO H, SO Na, K and the like) in the 2-position; wherein R is the residue of a diazotizable aryl amine or amino heterocyclic compound, and when B has a sulfonarnido substituent in the 2-position, R must contain a sulfo radical (e.g., SO H, SO Na, 80 K and the like).

The novel compounds of this invention are characterized by having excellent fiber substantivity, an aesthetically desirable hue as contrasted with an aesthetically undesirable green hue of some of the prior art brightening agents, a greater apparent whiteness than prior art compounds, outstanding resistance to bleaching agents commonly used in laundering processes, and excellent lightfastness. As a result of these remarkable properties fabrics Washed with soaps or other detergents containing small amounts of the novel compounds of this invention usually in the form of the sodium or other alkali metal salt become much brighter in the case of colors and whiter for others than fabrics which are washed either in the absence of such brightening agents or in the presence of the previously known brightening agents.

The compounds of this invention may also be incorporated in synthetic fibers and fabrics particularly during the manufacture thereof and especially in those of cellulose origin such as regenerated cellulose, cuprammonium cellulose, cellulose acetate and the like, by adding a small amount of the brightening agent to the spinning solutions or precipitating baths in order to achieve a noticeable increase in the whiteness of the finished product. These brighteners may also be used to effect a whitening of paper by the impregnation thereof (with the selected brightening agent) or by the incorporation of the brightening agent in the paper makingpulpprior to the final drying thereof. Additionally, the brightening agents of this invention may be employed to effect a whitening of waxes, gums and the like by adding small amounts of the agent to such substances.

The bistriazoles of this invention are prepared by coupling a 4-diazostilbene with a couplable 2-aryl-5-amino- 2,1,3-benzotriazole or 2-hetero-5-amino 2,1,3 benzotriazole and then oxidizing the resultant product to form a bistriazole in accordance with the following equation:

CH=CHMY coupled with III wherein R represents the groupings given above for (I) and Y is halogen (e.g., chlorine). The 4-diazostilbene compounds (II) useful in this invention include the following:

2-sulfo (or substituted sultonamido) diazostilbenes: 2-sulfo-4-diazostilbene 2-chloro-2-sulfo-4-diazostilbene 3-chloro-2-sulfo-4'-diazostilbene 4-chloro-2-sulfo-4-diazostilbene 2-bromo-2'-sulfo-4-diazosti1bene 3-bromo-2'-sulfo-4'-diazostilbene 4-bromo-2-sulfo-4-diazostilbene 2-methoxy-2-sulfo-4'-dlazostilbene 3-methoxy-2'-sulfo-4-diazostilbene 4-methoxy-2'-sulfo-4'-diazostilbene 2-methyl-2'-sulfo-4'-diazostilbene 3-methyl-2-sulfo-4'-diazostilbene 4-methyl-2'-sulfo-4-diazostilbene 2-(N,N-dimethy1-sulfonamido)-4-diazostilbene 2-(N,N-diethyl-sulfonamido)-4-diazostilbene 2-(N,N-bishydroxyethyl-sulfonamido)-4-diazostilbene 2-(N,N-diethyl-sulfonamido)-4-methoxy-4-diazostilbene The triazoles (III) operable in this invention are prepared in general by the oxidation of the product formed by coupling an organic diazo compound with m-phenylenediamine. The triazoles (III), above, and the bistriazoles (I) of this invention, as heretofore described, are prepared, after coupling to form the azo compound, by an oxidation step which results in the conversion of an ortho, primary amino group to a hetero atom of a triazole ring. The procedure for this oxidation may vary depending upon the choice of the oxidizing agent. For example, when one uses ammoniacal (or other organic base, e.g., pyridine, etc.) copper sulfate as the oxidizing agent, the resultant by-products of such reagent may be removed by adjustment of the pH of the solution, i.e., the reduction products of the oxidizing agents may be solubilized by making the solution more acidic, so that the by-products are removed in the filtrate by a filtration step. Alternatively, the by-products may be removed in the filtrate by making the reaction medium alkaline with ammonia (pH 11) prior to filtration. While it is preferred to use metallic (icous) oxidizing agents such as copper sulfate, ferric chloride, ferric NH SO etc., one may also employ hydrogen peroxide, KMnO K Cr O CaOCl NaOCl, Na perborate, oxygen, etc.

In preparing the various azo intermediates for the desired triazoles (I) and (III), the diamino containing coupling component in dilute aqueous solution or suspension is treated with a solution of a diazotized amine. In the case of compounds (III) the diazotized amines used are those represented by the R residue as given in Formulas I and III. Suitable amines as precursors for these diazotized compounds include:

aniline p-Sulfanilic acid sulfanilamide fl-Napththylamine amino pyridines, e.g.

fi-Amino pyridines such as 4 3-amino pyridine 3-amino-2-methoxy pyridine 3-amino-5-bromo pyridine 3-amino-2-chloro pyridine 5-amino-2-chl0ro pyridine o-Anisidine m-Anisidine p-Anisidine amino carbazoles, e.g.

l-amino carbazole Z-amino carbazole 3-amino carbazole 1-amino-6-methoxy carbazole 2-amino-4-methoxy carbazole l-amino-3,4-dibromo carbazole aminobenzothiophenes, e.g.

4-thianaphthenamine S-thianaphthenamine 4-bromo-S-thianaphthenamine In the case of the compounds of this invention (I) the diazotized amines (II) may be derived from the corresponding aromatic amino stilbenes described above.

The pH of the coupling reaction media may be varied according to the coupling component used. For example, in the coupling reaction involving the formation of the compounds of this invention (I) a pH of about 4 to 5 is preferred, although a pH as high as about 6.5 may be suitably employed to effect the desired azo coupling reaction. The couplings are preferably carried out in aqueous medium employing sodium acetate and acetic acid as bufiers although other means of maintaining the des red acidity may be employed. One may also employ pyridine as a coupling assistant in the manner well known in the azo coupling art. Similar conditions and pH ranges are used in the preparation of those intermediate alzfolfompounds which are the precursors for the triazoles The bistriazoles of this invention after the oxidation step may be recovered in the form of a paste by the filtration of the oxidation mixture and may be used in this form or dried to a powder. If desired, the bistriazoles may be purified by crystallization from a solvent, for example:

pyridine picoline formamide acetamide dimethyl formamide acetic acid, and the like.

Among the 2-aryl-5-amino-2,1,3-benzotriazoles and 2- hetero-S-amino-Z,1,3-benzotriazoles (III) which may be used as couplers or coupling components with the diazostilbene compounds (II) given above are the following:

2-phenyl-S-aminobenzotriazole Z-naphthyl-S-aminobenzotriazole 2- 2'-pyridyl -5-aminobenzotriazole 2- 3 '-pyridyl) -5-aminobenzotriazole 2- (4'-pyridyl -5-aminobenzotriazole 2-lutidyl-S-aminobenzotriazole S-aminobenzotriazolyl benzene o-sulfonic acid S-aminob enzotriazolyl benzene rn-sulfonic acid S-aminobenzotriazolyl benzene p-sulfonic acid 1- S-aminobenzotri azolyl naphthylaminel-sulfonic acid 1- S-aminobenzotriazolyl) naphthylamine-S-sulfonic acid 1- (S-aminobenzotriazolyl) naphthylamine-G-sulfonic acid 1- S-aminobenzotriazolyl) naphthylamine-7-sulfonic acid 1- S-aminobenzotriazolyl naphthylamine-S-sulfonic acid 2- S-aminobenzotriazolyl naphthylamine-S-sulfonic acid 2-(S-aminobenzotriazolyl)naphthylamine-d-sulfonic 13.8 parts of 4-amino-2-stilbenesulfonic acid is disacid solved in 200 parts water and 10 parts of 40% sodium 2-(S-aminobenzotriazolyl)naphthylamine-7-sulfonic hydroxide solution. The solution is cooled to C. and

acid acidified with 27.3 parts concentrated hydrochloric acid 2-(S-aminobenzotriazolyl)naphthylamine-S-sulfonic 5 (specific gravity 1.19). The suspension of aminostilacid and the corresponding sulfonamides benesulfonic acid is diazotized by adding a solution of 2(o-methoxyphenyl)-5-aminobenzotriazole 3.5 parts sodium nitrite in 25 parts water at 0 C. during 2(m-methoxyphenyl)-5-aminobenzotriazole one and one-half hours. The slight excess of nitrous 2(p-methoxyphenyl)-5-an1inobenzotriazole acid is destroyed by the addition of 6 parts 10% sul- 2-(2-[l-chloro]naphthyl)-5-aminobenzotriazole 10 famic acid. The diazo solution is added to a solution of 2-(2-[3-chloro1naphthyl)-5-aminobenzotriazole 10.5 parts 2-phenyl-5-amino-2,1,3-benzotriazole and 262 2-(2-[4-chloro1naphthyl)-5-aminobenzotriazole parts glacial acetic acid. 200 parts of 30% sodium 2-(2-[S-chloro]naphthyl)-5-aminobenzotriazole acetate solution is added to raise the pH to 4-5 and the 2-(2-[6chloro]naphthyl)-5-aminobenzotriazole mixture is stirred for 12 hours. After the coupling is 2-(2-[7-chloro]naphthyl)-5-arninobenzotriazole 15 finished the azo dye is filtered and washed with water. 2-(2-[8-chloro]naphthyl)-5-aminobenzotriazole The wet presscake is slurried with 196 parts pyridine. Z-(acetamidophenyl)-5-aminobenzotriazole A solution of parts cupric sulfate (CuSO .5H O) and 2-(benzamidophenyl)-5-aminobenzotriazole 200 parts Water is added and the mixture is heated Z-(S-[acetamidonaphthyl])-5-aminobenzotriazole to reflux for 12 hours. The reaction mixture is cooled 2-(m-trifluoromethyl)phenyl-S-aminobenzotriazole 20 to 10-15 C., filtered and washed. The triazole product 2-(4-carbalkoxyphenyl)-5-aminobenzotriazole is dried in a vacuum oven at 70-75 C.

Example 3 2-(carbamidophenyl)-5-aminobenzotriazole 13.8 parts 4-amino-2-stilbenesulfonic acid are dis- 2-(o-acetophenyl)-5-aminobenzotriazole 0 solved in 200 parts water and 10 parts 40% sodium 2-(m-acetophenyl)-5-aminobenzotriazole hydroxide solution. 'The solution is cooled to 0 C. and 2-(p-acetophenyl)-5-arninobenzotriazole 17.9 parts concentrated hydrochloric acid are added. The 2-(o-benzoylphenyl)-5-aminobenzotriazole suspension of the aminostilbenesulfonic acid is diazotized 2-(m-benzoylphenyl)-5-aminobenzotriazole with a solution of 3.5 parts sodium nitrite and 25 parts 2-(p-benzoylphenyl)-5-aminobenzotriazole and th water during one and one-half hours at 0 C. The exlike cess nitrous acid is decomposed by the addition of 5.5

parts of a 10% sulfamic acid solution. The diazo solution is added to a solution of 14.5 parts 2-(4-sulfophenyl)-5-amino-2,1,3-benzotriazole (prepared by coupling diazotized sulfanilic acid to meta-phenylenediamine The following examples in which the parts are by weight unless otherwise indicated are illustrative of the instant invention and are not to be regarded as limitative thereof.

Example 1 6.9 parts of 4-arnino-Z-stilbenesulfonic acid is disand oxidizing theazo dye formed to the corresponding solved in 100 parts water and 8 parts of 40% sodium triazole with an ammoniacal cupric sulfate solution), hydroxide solution. The solution is cooled to 0-5 C. 2000 parts water and 10 parts 40% sodium hydroxide and 17.9 parts concentrated hydrochloric acid (specific solution. 250 parts of 30% sodium acetate solution are gravity 1.19) is added. The fine suspension of the aminoadded to raise the pH to 4-5 and the mixture is stirred stilbenesulfonic acid is diazotized by the addition of a for 12 hours. After the coupling is finished, 150 parts solution of 1.8 parts sodium nitrite in 20 parts Water common salt are added and the mixture is cooled to during one and one-half hours at 0-5 C. The excess 20 C. The azo dye is filtered, pressed as dry as posnitrous acid is destroyed by the addition of 4 parts of sible and the cake is slurried with 245 parts pyridine. 42 10% sulfanic acid solution. The diazo solution is added parts cupric sulfate (CuSO .5H O) dissolved in 100 parts rapidly to a solution of 7.3 parts 2-(4'-sulfonarnido-, Water are added and the mixture heated to 90-95 C. phenyl)-5-amino-2,1,3-benzotriazole (prepared by coufor four hours until the triazole formation is completed. pling diazotized sulfanilamide to meta-phenylenediamine 500 parts water are added and the reaction mixture cooled at a pH of 5 and oxidizing the azo dye formed to the cor to 15-20 C., filtered and the product dried.

responding benzotriazole) and 343 parts pyridine and 50 I parts water. After coupling is finished, the azo dye mix- Example 4 ture is acidified with 416 parts concentrated hydrochloric $03K acid, filtered and the wet cake heated with 196 parts pyridine and 25 parts cupric sulfate (CuSO .5l-I O) pre- O viously dissolved in 200 parts of Water to 90-95 C. for II II 16 hours. Upon cooling, the product is filtered and dried SO Na N==N in a vacuum oven at -75 C.

Example 2 The procedure of Example 3 is followed except that OOH=CHO NI|\I F 17.8 parts of 2-(5-aminobenzotriazolyl)naphthalene-4,8- 1 L i disulfom'c acid is used in place of 14.5 parts of 2-(4-sul- S T fophenyl)-5-amino-2,1,3-benzotriazole.

7 8 Example The procedure of Example 4 is again repeated employing 15.5 parts of 4-amino-4-chloro-2-stilbenesulfonic acid C O in lieu of the 13.8 parts of the stilbene compound de- I I I I scribed in Example 4.

sOaNa Example 11 S0311 =o11 N--N N.N The procedure of Example 3 is followed except that I I II I 51 N:

13.8 parts of 2'(5-aminobenzotriazolyl)naphthalene-S- Naoas sulfonic acid is used in place of 145 parts of 2-(4-sulfophenyl)-5-amino-2,1,3-benzotriazole. SOBH Example 6 The procedure of Example 1 is repeated employing in The procedure of Example 4 is again repeated employlieu of the 6.9 parts of 4-amino-2-stilbenesulfonic acid, ing 15.5 parts of 4-amino-3'-chloro-Z-stilbenesulfonic acid 7.2 parts of 4-amino-4'-methyl-2-stilbenesulfonic acid. as the stilbene moiety.

Example 7 Example 12 The procedure of Example 2 is repeated employing SOzN CHK 14.5 parts of the stilbene compound described in Example 6 in lieu of the 13.8 parts of that of Example 2. 011a Example 8 IFTQ-SWH The procedure of Example 3 is repeated employing 15.2 parts of 4-amino-4'-methoxy-Z-stilbenestflfonic acid The prpcedure of Example 3 is repeated employing in place of the 13.8 parts of the stilbene compound of 15.2 parts of 2(N,N-dimethyl-sulfonamido)-4-aminostil- Example 3.

Example 9 O -t FIG don. some N==N The procedure of Example 3 is again repeated employing 15.2 parts of 4-amino -2-methoxy-2-stilbenesulfonic bene in lieu of the 13.8 parts of the stilbene compound of acid in lieu of the 13.8 parts of the stilbene compound of Example 3. Example 3. 65

Example 10 9 10 Example 13 g. sodium m-bisulfite per 1. of solution) is added to destroy the Clorox and 5 parts Indian Head cotton fabric is -CH=CH' :}NN N'N C SO3H added. The solution is then placed in a launderometer I I for minutes at 130 F. The cotton swatch after rinsing twice in warm tap water and air drying at 55 C. has 5 a brightness value of 73.4 in the adapted fluorescent SOtN0eHtoH photometer. It will thus be observed that the brightness (321340;; of the resultant product actually has increased by about 13% above that obtained above in the absence of the Clorox solution. The procedure is again repeated except that the Clorox is destroyed after 20 minutes at the 130 F. temperature. The resultant cotton swatch The procedure of Example 3 is repeated except that 18.5 parts of 2(N,N-bishydroxyethyl-sulfonamido)-4- 10 aminostilbene is used in place of the 13.8 parts of the stilbene compound of Example 3.

Example 14 i t TQ SOzN CgHis The procedure of Example 3 is again repeated using has a brightness value of 71.0 which is a 9% increase in 18.5 parts of 2(N,N-diethyl-sulfonamido)-4-amino-4- brightness over the comparable sample dyed in the absence methoxystilbene in place of the 13.8 parts of the stilbene of the Clorox. compound of Example 3. Example C Example A The procedure of Example A is repeated employing three dlfferent concentrations of the blstrlazole of Exbnghtenmg ageht of Example 15 tested for bnght' ample 3. These concentrations are 0.00016 part, 0.00032 11655 1D accordance Wlth P folloYvlflg Procedure- To part, and 0.004 part in 100 parts of a water solution, each 100 Parts of a water Solutlon coma-111mg 100016 Part of of the said solutions also containing 0.4 part of Superthe histriazole of Example 1 e P of supersuds suds as above described. The resultant cotton swatches there is added 5 parts of Indian Head cotton fabric in a ft ringing and drying had brightness values for the lauhdemmeter- The fabric is maintained at 1300.13: lowest concentration of dyestuif of 64.3, for the interme- 20 mlmltes 111 the y The cotton Swatch h diate concentration 83.9, and for the highest concentra-, given 2 rinses in lukewarm tap Water and fihauy elf e tion 148. Again these values far exceed any brightness at 55 The hflghhless 0f the fesulhhg FY0511ct 1S values heretofore obtainable with other acceptable brightmeasured in an adapted fluorescent photometer and is eners.

found to give a brightness reading of which value for The chlorine stability of this product is tested in the the dye concentration herein used far exceeds the results manner i il to h d ib d i E l 3, h obtained y other commercially acceptable brlghteners- 40 centration of the d estnir again being 0.00032. The On vlsual eomrarlsen the product pp much Winter brightness value obtained after the 5 minute ClOIOX" than t heIetOfOfe Obtained fluorescent y produetstreatment is 90.3, which represents an 8% increase in A Similar Procedure is carried out except that the histribrightness as compared to the 83.9 value obtained at this aZOle eoheelltfatieh p y is 090932 P P 100 Parts concentration in the absence of the Clorox. The brightof solution. The brightness reading at this concentration s reading obt ined fter the 20 minute Clorox treatis 66.8. ment is 92.3, which represents a 10% increase in bright- Example B ness over the sample not subjected to the ,Clorox treatment.

The bistriazole of Example 2 is tested for brightness The products of Examples 4 through 14 exhibit similar in the same manner described above in Example A. The outstanding brightness values of Clorox stability and,

brightness readings obtained on the product dyed with a additionally, all of the products of Examples 1 through 14 solution containing 0.00016 part of bistriazole per 100 exhibit excellent light-fastness characteristics.

parts of solution is 46.8. At twice this concentration, Various other modifications and variations of this inthat is, 0.00032 part bistriazole per 100 parts of solution, vention will be obvious and apparent to those skilled in the brightness reading is 63.3. This product is further the art and it is to be understood that such modifications tested for its chlorine stability in the following manner. and variations are to be included within the purview of parts of a water solution containing 0.00032 part of this application and the spirit and scope of the appended bistriazole, 25 parts Clorox solution (15 parts Clorox claims. containing 0.052 g. active chlorine per ml. in 1000 parts We claim: water), and 0.4 part Supersuds are heated to F. 1. Acompound having the formula:

' 3 Sulfo N: =N After 5 minutes suflicient sodium m-bisulfite solution (2.5 2. A compound having the formula:

Q I -i i- 011,0Ht0H sotN CHiCHzOH 11 12 3. A compound having the formula: 7

CgHs

SOzN

References Cited in the file of this patent UNITED STATES PATENTS 2,462,405 Keller et a1 Feb. 22, 1949 2,713,057 Zweidler et a1 July 12, 1955 2,784,197 Zweidler Mar. 5, 1957 2,817,665 Zweidler Dec. 24, 1957 FOREIGN PATENTS 162,426 Australia Apr. 13, 1955 1,071,727 France Sept. 3, 1954 OTHER REFERENCES Venkatararnan: Synthetic Dyes, vol. 2, page 1217, Academic Press Inc. (1952). 

1. A COMPOUND HAVING THE FORMULA: 